Fill blue cells (water) in the grid . The numbers tell how much water cells are in this row or column. In a box (fish tank) the water falls down. In the same box within the same line either all cells must be water or none.

Fill blue cells (water) in the grid . The numbers tell how much water cells are in this row or column. In a box (fish tank) the water falls down. In the same box within the same line either all cells must be water or none.